Noncardiac Pulmonary Edema.

 Noncardiac pulmonary edema (NCPE)

PKGhatak, MD

Pulmonary Edema is an acute illness due to fluid accumulation in inter-alveolar connective tissues and in the alveolar spaces of the lung. The most common cause of acute pulmonary edema is Left Ventricular failure from a massive left ventricular infarction. However, pulmonary edema also happens from other than an acute left ventricular failure. These conditions are called Noncardiac Pulmonary Edema (NCPE)

NCPE: 

The basic mechanism of NCPE is alveolar capillary leak. There are various reasons or conditions leading to capillary leak producing pulmonary edema. The characteristic features of NCPE are that the pulmonary capillary wedge pressure (PCWP) and PAP (pulmonary artery pressure) remain normal or low, and the ratio of protein in pulmonary edema fluid and serum protein is over 0.7.

Common causes of NCPE.

 1.Covid-19 induced cytokine storm. 2. Adult respiratory distress syndrome (ARDS) resulting from gastric aspiration, pancreatitis, sepsis, open chest cardiac surgery, chest trauma, drug overdose. 3. Pulmonary embolism. 4. Neurogenic - seizures, Brain surgery, subarachnoid hemorrhage, meningitis. 5. Narcotic overdose. 6. High altitude pulmonary edema (HAPE). 6. Toxic gas inhalation, Thermal injury to lungs in open flame fire incidences. 7. Salicylate intoxication. 8. Transfusion related acute lung injury (TRALI) 8. Near drowning. 

Other causes of NCPE: - Reperfusion and re-expansion pulmonary edema. Fluid overload. Post obstructive. Following the lung transplant. Drug reaction and hypersensitivity reaction. Exercise induced. Air embolism.

Diagnosis.

When a patient presents with acute respiratory distress, coughing up pink frothy sputum, extreme anxiety and altered consciousness with signs of overworked muscles of respiration, central cyanosis, moist rales on auscultation, various degrees of shock, the diagnosis of Pulmonary edema is not difficult. Low oxygen saturation in digital oximetry, X-ray shows no cardiac enlargement, no dilatation of major branches of the pulmonary artery. Bilateral peripheral symmetrical " batwing" opacities the diagnosis is made. ECG will show no right/left ventricular strain, hypertrophy or major arrhythmia. Rarely fluid/serum protein ratio or PCWP are required for the diagnosis of NCPE. The history of the illness will clearly point toward the cause.

The newer Ultrasound devices can detect septal edema, and thickened minor fissures in NCPE are reported as B lines. The B lines are artifacts generated by reverberations of sound waves and appear generally in a group of three, separated by 7 mm one group from the next group.

Treatment.

Immediate oxygen therapy is instituted by the first responders, then proper oxygenation has maintained by any means, and when respiratory failure is also present noninvasive or invasive mechanical ventilation is instituted.

Other modalities of therapy vary according to the etiology of NCPE.

Prognosis. NCPE outcome is much better than cardiac pulmonary edema.

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